Trump "Walk of Fame" trolls Biden with autopen signature in place of portrait

Context: An autopen is a device which makes automatic or remote signatures, which Trump, Biden and other presidents have acknowledged using.

Catch up quick: Trump and his allies have claimed documents signed by Biden using autopen may be invalid.

• Trump did so as recently as last week during a news conference in the U.K.
• Biden told The New York Times in July he "made every decision" and had orally granted all the pardons and commutations he issued at the end of his presidency.
• He said he used the autopen on his record-setting number of pardons and commutations because "we're talking about a whole lot of people."

Flashback: Former President Obama faced scrutiny in 2011 for using an autopen to sign the Patriot Act's extension, a first for a president.

• A 2005 Justice Department memorandum said the president may sign a bill by directing a subordinate to "affix the President's signature to it."

• "We emphasize that we are not suggesting that the President may delegate the decision to approve and sign a bill, only that, having made this decision, he may direct a subordinate to affix the President's signature to the bill," the memorandum stated.

Reality check: Jeffrey Crouch, an American University professor and expert in federal executive clemency, told Axios in March that "other presidents have used autopen to grant pardons."